Many studies have shown important changes in lung function tests after coronary artery surgeries. It is controversial if off-pump surgery can give a better and shorter recovery than the on-pump. The aim of this work was to study immediate early pulmonary dysfunction in ischemic heart disease patients undergoing off-pump versus on-pump coronary artery bypass grafting (CABG) in order to evaluate pulmonary dysfunction caused by cardio-pulmonary bypass (CPB) in patients undergoing on-pump CABG.